National Water Summary Wetland Resources: New Mexico
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National Water Summary-Wetland Resources 285 New Mexico Wetland Resources Wetlands cover about 482,000 acres (0.6 percent) of New Mexico, wetlands, whereas the other systems comprise wetlands and a reduction of about 33 percent from the wetland acreage that ex deepwater habitats. Wetlands of the systems that occur in New isted about 200 years ago (Dahl, 1990). New Mexico's wetland acre Mexico are described below. age places the State 34th in total wetland acreage among the 48 conterminous States. System Wetland description Wetlands are ecologically important and economically valu able to the State. Wetlands provide important wildlife habitat. For Palustrine .................. Wetlands in which vegetation is predominantly example, in the Rio Grande Valley, wetlands provide habitat for 246 trees (forested wetlands); shrubs (scrub-shrub wetlands); persistent or non persistent emergent, species of birds, 10 species of amphibians, 38 species of reptiles, erect, rooted, herbaceous plants (persistent- and and 60 species of mammals (U.S. Fish and Wildlife Service, 1990). nonpersistent-emergent wetlands); or sub Wetlands also provide stopover, feeding, and breeding grounds for mersed and (or) floating plants (aquatic beds). migratory waterfowl (fig. 1). Also, intermittently to permanently flooded open-water bodies of less than 20 acres in which Riparian (streamside) wetlands along perennial streams are water is less than 6.6 feet deep. important as migration corridors for a variety of waterfowl and other Lacustrine ................. Wetlands within an intermittently to permanently wildlife. The playa lakes in eastern New Mexico are vital links in a flooded lake or reservoir. Vegetation, when pres chain of wetlands along the Central Flyway, which extends from ent, is predominantly nonpersistent emergent central Canada to the coast of Texas. Areas of springs and marshes plants (nonpersistent-emergent wetlands), or provide essential habitat for many rare and endangered species and submersed and (or) fl oating plants (aquatic beds), or both. for indigenous fish and wildlife in the western part of the State. Wetlands contribute to flood attenuation, bank stabilization, Riverine ..................... Wetlands within a channel. Vegetation, when pres- ent, is same as in the Lacustrine System. and improved water quality. New Mexico's tourist industry benefits from the beauty of the State's diverse wetlands. These wetlands pro Although wetlands occur in all areas of New Mexico, they are vide opportunities for recreational activities that include fishing, most numerous in the eastern and northern areas of the State (fig. hunting, bird watching, nature photography, camping, and hiking. 2A ). In the Southern Rocky Mountains (fig. 28 ), wetlands are mostly in high mountain valleys and intermountain basins. In the TYPES AND DISTRIBUTION Great Plains, wetlands occur along the flood plains of the Canadian and Pecos Rivers and in association with playa lakes. ln the Colo Wetlands are lands transitional between terrestrial and rado Plateaus and Basin and Range, wetlands are sparsely distrib deepwater habitats where the water table usually is at or near the uted, with the exception of wetlands associated with the San Juan, land surface or the land is covered by shallow water (Cowardin and San Francisco, and Gila Rivers. others, 1979). The distribution of wetlands and deepwater habitats Palustrine wetlands are distributed statewide. In New Mexico, in New Mexico is shown in figure 2A; only wetlands are discussed palustrine wetlands include forested wetlands in river flood plains herein. and near springs and seeps; scrub-shrub wetlands such as bottom Wetlands can be vegetated or nonvegetated and are classified land shrubland; emergent wetlands, such as marshes, fens, alpine on the basis of their hydrology, vegetation, and substrate. In this snow glades, and wet and salt meadows; aquatic bed wetlands in summary, wetlands are classified according to the system proposed shallow ponds and small lakes; and sparsely or nonvegetated wet by Cowardin and others ( 1979), which is used by the U.S. Fish and lands such as playa lakes. Palustrine wetlands along rivers, streams, Wildlife Service (FWs) to map and inventory the Nation's wetlands. springs, lakes, and ponds are called riparian wetlands. Riparian At the most general level of the classification system, wetlands are wetlands along the State's major rivers provide habitat for fish, wild grouped into five ecological systems: Palustrine, Lacustrine, Riv life, and diverse plant life. They also provide habitat for migrating, erine, Estuarine, and Marine. The Palustrine System includes only overwintering, and nesting waterfowl. One of the more notable ri parian wetlands in New Mexico is in the Bosque del Apache Na tional Wildlife Refuge. The 57,191-acre refuge lies along 9 miles of the Rio Grande in south-central New Mexico. Marshes within the refuge are ideal winter habitat for migratory birds, including ducks, geese, sandhill cranes, and whooping cranes. Efforts are being made to maintain and restore native riparian cottonwood habitat in the refuge for a variety of birds and other wildlife. Many western spe cies of riparian trees and shrubs, such as willows and cottonwoods, have been lost because of nonnatural streamflow regimes (Howe and Knopf, 1991). The nonnatural flows followed the completion of water projects in the first half of the 20th century, resulting in rapid colonization and expansion of the exotic Russian-olive and salt ce dar. The playa lakes of eastern New Mexico provide habitat for Figure 1. Bosque del Apache National Wildlife Refuge. These migrating, overwintering, and nesting waterfowl in the Central Fly riparian wetlands provide habitat for migratory and resident way (U.S. Fish and Wildlife Service, 1990). The estimated number waterfowl, fish, and other wildlife. (Photograph by Lisa Carter, of playa lakes in the State is 1,700, and they range in area from less U.S. Geological Survey.) than 1 acre to more than 600 acres (Nelson and others, 1983). The 286 National Water Summary- Wetland Resources: STATE SUMMARIES playa lakes range in wetness from dry lake bed to shallow lake and someti mes within the physiographic provinces. New Mexico's di can be fresh or saline. The freshwater playas are numerous, small verse physiography, climate, and topography result in diverse hy to medium in size, and serve as zones of recharge to the underlying drologic settings for wetland formation. aquifer (Osterkamp and Wood, 1987). The saline playas are larger In the Colorado Plateaus and Basin and Range Provinces (fig. and fewer than the freshwater playas and are areas of discharge from 28), wetlands occur in springs and seeps, around oxbow lakes, along the underlying aquifer. Most playa lakes in New Mexico are streams and rivers, around reservoirs, and in other areas where the palustrine. However, playa lakes larger than 20 acres are classified water table is near the land surface. The arid climate of this region as lacustrine wetlands, as are the shallow areas of large reservoirs. results in a low density and acreage of wetlands. Wetlands, although Riverine wetlands occur in the shallow river channels of pe few in number, are vital to wildlife of these physiographic provinces. rennial streams. There are about 3,500 miles of streams in New In the Great Plains, wetlands occur in riparian zones along Mexico (Ong and others, 1993). perennial streams, around oxbow lakes, in isolated natural depres sions with permanent or seasonal water supply, in playa lakes, and in association with other lakes, reservoirs, channelized streams, HYDROLOGIC SETTING rivers, and irrigation ditches. Playa lakes make up the largest area Wetlands form where a persistent water supply is at or near of wetlands in this province. the land surface. The location and persistence of the supply of water The area of playa lakes has topography classified as either is a function of precipitation and runoff patterns, evaporation po smooth plains, irregular plains, or tablelands (Nelson and others, tential, topography, and the presence of a shallow water table. 1983). Smooth plains are largely on upland terrain, and irregular Precipitation and runoff rates differ annually and with loca plains and tablelands are mostly on lowland terrain. Because of the tion and season. Average annual precipitation in New Mexico (fig. flatness of the terrain, there is generally little stream drainage, and 2C) ranges from about 8 inches in the northwestern corner of the playa lakes collect most of the surface runoff. The playa lakes are State and in the southern Rio Grande Valley to 24 inches in the mountains of A the northern and southern parts of the State. Runoff (fig. 2D) is greatest in the northern mountains and smallest in the desert areas of the southern and east ern parts of the State. Much of the run off from the mountains occurs during concurrent snowmelt and rainfall in the spring and summer. Average annual pan evaporation varies across the State and ranges from about 40 to 112 inches per year (Nelson and others, 1983). Most evaporation occurs from March through September and decreases with increasing altitude. Because annual evaporation exceeds annual rainfall, most of the State has a net annual moisture deficit. The mois ture deficit is a limiting factor in the formation of wetlands and to the con tinued existence of some of the more fragile wetlands. Even those areas of the State having the highest precipita tion and lowest evaporation (high mountain regions) can be unfavorable for development of wetlands because of steep topography, shifting stream chan nels, and unfavorable soil conditions (Cooper, 1986). ... Shallow water tables and ground water discharge into topographic de ~:_, pressions, streams, and springs main ___j tain wetlands in many areas of New 32°1 ----~ --------\l-.---.!...L__ _ Mexico. These wetlands can be along \ small streams that have perennial flow -----~ WETLANDS AND DEEPWATER HABITATS I I Distribution of wetlands and deepwater habitats- in only short reaches or along larger, l_ ___ , This map shows the approximate distribution of large perennial streams.